I like this because it doesn't have any other ingredients in it. I don't necessarily like using a powder form of Calcium but I prefer it to tablets and the caplets all had some other ingredient that I'm allergic to.

I have a hiatial hernia and can't swallow pills, so I am very grateful for the powders NOW provides. Since I can't know the reliability of the different companies, I trust iHerb not to sell me anything of low quality.

This one does not work for me. I have been trying several different calcium supplements out there, because my stomach is very sensitive to almost any kind of calcium. This one is the worst! As soon as I took it my stomach was on fire, it gave me severe acid reflux and I could not even vomit it to have some relieve. It might work for you though!

This is a fine, bio-available calcium. I use 2 tsp. (I need a lot), four times per day (between meals). I take it together with Dr's Best magnesium, vitamin A (from fish liver oil), and vitamin D (cholecalciferol).